Organic Light-Emitting Diodes Based on Poly(9,9-dioctylfluorene-co-bithiophene) (F8T2)

A study of the optical properties of poly(9,9‐dioctylfluorene‐co‐bithiophene) (F8T2) is reported, identifying this polymer as one that possesses a desirable combination of charge transport and light emission properties. The optical and morphological properties of a series of polymer blends with F8T2 dispersed in poly(9,9‐dioctylfluorene) (PFO) are described and almost pure‐green emission from light emitting diodes (LEDs) based thereon is demonstrated. High luminance green electroluminescence from LEDs using only a thin film of F8T2 for emission is also reported. The latter demonstration for a polymer previously primarily of interest for effective charge transport constitutes an important step in the development of emissive materials for applications where a union of efficient light emission and effective charge transport is required. The optical properties of poly(9,9‐dioctylfluorene‐co‐bithiopehene) (F8T2) (see diagram), a polymer already known for its effective charge carrier transport, are studied in this work. The demonstration of bright green electroluminescence (EL) from polymer light‐emitting diodes (PLEDs) based on F8T2 could be of interest in the development of emissive materials not only for PLEDs, but also for organic light‐emitting field‐effect transistors (FETs) and electrically pumped organic lasers, where a union of efficient EL and effective charge transport is required.